The implantation of synthetic tubular prostheses to replace or buttress damaged or diseased vascular vessels or other luminal passageways within the human body is well known. Synthetic tubular prostheses include grafts as well as endoprosthetic devices.
Tubular prostheses such as grafts are most commonly implanted by surgical techniques. Typically, a surgeon sutures the graft in place within the blood vessel or other body passageway to be repaired in an open surgical technique. Intraluminal implantation is also a common technique for implanting tubular prostheses. This procedure typically involves percutaneous insertion of an endoprosthesis by way of a delivery catheter. This procedure permits delivery and implementation without the need for major surgical intervention and the risks inherent therewith. Thus, intraluminal implantation of various prosthetic devices via delivery catheters is becoming increasingly common.
With respect to grafts and other prostheses which may traditionally be surgically implanted, means other than suturing must be used to secure these prostheses in place within the body passageway in order to effectively permit intraluminal implantation. It is known to employ stents in combination with grafts and various other prostheses in order to support and secure such a device in place within the body passageway after implantation. Stents are typically radially expandable and/or contractible support members which are positioned within a graft or other tubular prosthesis. In common usage, after a prosthesis has been properly positioned, the stent is expanded to anchor the prosthesis within the body passageway.
Since a stent must be expanded to support the prosthesis within the body passageway for implantation, the delivery system used to transport the stent to the location of implantation must be capable of maintaining the stent in a compressed state during delivery and implantation until such time a stent deployment is necessitated. Attempts have been made to improve delivery systems for compressed stents. Several disclosures relate to such systems.
U.S. Pat. No. 4,950,227 discloses a catheter delivery system for a stent wherein the stent is positioned about a balloon-type catheter and held in position by a sleeve fixing the end of the stent. As the balloon is inflated, the stent is expanded, causing the sleeve to slide off of the stent and release the stent.
U.S. Pat. No. 5,108,416 discloses a catheter delivery system for a stent wherein the stent is positioned about a balloon type catheter and held in position by end caps. As the balloon is inflated, the end caps move away from the stent and release the stent.
U.S. Pat. Nos. 5,158,548 and 5,242,399 disclose a stent delivery system wherein a stent is positioned about a balloon-type catheter and held in position by an outer sheath. A guidewire attached to the outer sheath is moved forward, thereby moving the sheath forward to expose and release the stent.
Accordingly, a need exists for an effective system for catheter delivery and deployment of a stent-supported implantable tubular prosthesis.